In the movement of network data packets, the overhead of moving a packet from one network device to another network device is known as latency. When bridging network data packets from one media to another media, mostly of different speeds, the packets are temporarily stored for preparation to be sent out the other media. This is known as store-and-forward. When combining two wireless, half duplex links, to form a full duplex link, extra packet store-and-forward's occur when gateways are introduced at either end of the link to control the flow of packets and prevent loops from occurring on the network. Removing the gateways by which the packet travels over the network improves the latency, which means better performance over the connection for the user.
With the development of the PHY (Physical Layer in the OSI Model), MAC (OLI Model Layer 2—data link layer), and the digital interface bus by which the MAC and PHY communicate, called the MII bus, the IEEE has defined a much simpler way for network devices to be developed and interoperate with each other. Newer variants of the MII bus have been developed, allowing many different bus definitions with much better functionality.